The Steel Guitar Forum Store 

Post new topic Yet Another Chip Mod Question(s)
Reply to topic
Author Topic:  Yet Another Chip Mod Question(s)
Jack Stanton


From:
Somewhere in the swamps of Jersey
Post  Posted 18 Sep 2017 9:11 am    
Reply with quote

1.Is it correct that Texas Instruments bought Brown Burr, and so theoretically they one and the same?

2. Mouser's website shows 4 different OPA1642 chips, each with a different letter suffix. I'm assuming there's a difference, but you know what happens when you assume..

3. In previous threads Ken Fox mentioned that he doesn't change the IC for the reverb as it may self oscillate. Can anyone enlighten me as to which one is for the reverb?

I'll take my answer off the air....
View user's profile Send private message Send e-mail

Bob Metzger

 

From:
Waltham (Boston), MA, USA
Post  Posted 18 Sep 2017 9:57 am    
Reply with quote

What type/model amplifier or effects unit are you asking about?

Bob M.
_________________
Bob M.
View user's profile Send private message Send e-mail

Jack Stanton


From:
Somewhere in the swamps of Jersey
Post  Posted 18 Sep 2017 9:59 am    
Reply with quote

Sorry, Nashville 400
View user's profile Send private message Send e-mail

Steven Paris

 

From:
Los Angeles
Post  Posted 18 Sep 2017 10:15 am     Re: Yet Another Chip Mod Question(s)
Reply with quote

Jack Stanton wrote:

1.Is it correct that Texas Instruments bought Brown Burr, and so theoretically they one and the same?
2. Mouser's website shows 4 different OPA1642 chips, each with a different letter suffix. I'm assuming there's a difference, but you know what happens when you assume..
3. In previous threads Ken Fox mentioned that he doesn't change the IC for the reverb as it may self oscillate. Can anyone enlighten me as to which one is for the reverb?
I'll take my answer off the air....

1. Yes, TI owns Brown-Burr
2. The OPA suffixes AIDGKR and AIDGKT are VSSOP-8 packages--VERY small. Avoid unless you are an experienced surface-mount solderer. The only difference I can see between the AID and AIDR suffixes (both are SOIC-8 packages) is the packaging quantity (75 vs 2500) and the price ($4.00 vs. $3.33). So I'd stick with the AIDR.
3. The IC for reverb drive is U5B in a Peavey Nashville 400. I believe the reason for possible oscillation is that the power supply bypass cap FOR THIS IC ONLY is much farther away than ideal, and farther away than any of the other ICs. An 0.1 cap soldered between pins 4 and 8 on the solder side of IC 5 should cure this.
Keep in mind that if you are replacing the socket-mounted chips that you will need an SOIC-to-DIP adapter board (https://www.sparkfun.com/products/13655) for EACH OPA1642 IC.
The OPA1642 does offer slightly superior specs to an OPA2134; but the 2134 is available in a traditional DIP-8 package which, the 1642 is NOT. Whether this difference is audible or not in a steel guitar amplifier is open for question. The 2134 will simply pop into a DIP socket and therefore might be the better choice. BOTH of these chips are VASTLY superior to the stock RC4558 chip.
_________________
Emmons & Peavey


Last edited by Steven Paris on 18 Sep 2017 10:23 am; edited 1 time in total
View user's profile Send private message Send e-mail

Jack Stanton


From:
Somewhere in the swamps of Jersey
Post  Posted 18 Sep 2017 10:18 am    
Reply with quote

Steven,
Thank you!
2134 it is..
View user's profile Send private message Send e-mail

Jack Stoner


From:
Kansas City, MO
Post  Posted 19 Sep 2017 2:23 am    
Reply with quote

A steeler friend (an EE) and I upgraded the chips in two Nashville 400's. Mine had the original Peavey factory installed tone mod (that didn't change the op-amps) and his had the Lemay mod (that did change some of the op-amps). We put the new OPA op-amps in and in these two tone modded amps it made no hearable difference.
_________________
GFI Ultra Keyless S-10 with pad (Black of course) TB202 amp, Hilton VP, Steelers Choice sidekick seat, SIT Strings
Cakewalk by Bandlab and Studio One V4.6 pro DAWs, MOTU Ultralite MK5 recording interface unit
View user's profile Send private message Send e-mail

Jack Stanton


From:
Somewhere in the swamps of Jersey
Post  Posted 19 Sep 2017 5:05 am    
Reply with quote

Jack,
Fair chance you may be absolutely correct, but for the price, I'll give it a go and report back.
View user's profile Send private message Send e-mail

Bob Metzger

 

From:
Waltham (Boston), MA, USA
Post  Posted 19 Sep 2017 9:47 am    
Reply with quote

A little repetition of Steven Paris's post but with my reverb mod kit for the Peavey Nashville 400 amp I recommend using the Burr-Brown op amp:

IC5 is for the reverb drive and recovery and I recommend that you change it to the better performing Burr-Brown OPA 2134PA if you have an earlier model NV 400, prior to the incorporated preamp mod (the Peavey Tone Enhancement Mod). The ICs in this amp are socketed and the IC I recommend is exact pinout compatible; just remove the old one and drop in the upgrade IC, noting the correct orientation.

Bob M.
_________________
Bob M.
View user's profile Send private message Send e-mail


All times are GMT - 8 Hours
Jump to:  

Our Online Catalog
Strings, CDs, instruction,
steel guitars & accessories

www.SteelGuitarShopper.com

Please review our Forum Rules and Policies

Steel Guitar Forum LLC
PO Box 237
Mount Horeb, WI 53572 USA


Click Here to Send a Donation

Email admin@steelguitarforum.com for technical support.


BIAB Styles
Ray Price Shuffles for
Band-in-a-Box

by Jim Baron
HTTP